Mass death among baby right whales has experts scrambling to figure out the puzzle behind the largest great whale die-off on record.

Observers have found 308 dead whales in the waters around Peninsula Valdes along Argentina's Patagonian Coast since 2005. Almost 90 percent of those deaths represent whale calves less than 3 months old, and the calf deaths make up almost a third of all right whale calf sightings in the last five years.

"This is the single largest die-off event in terms of numbers and in relation to population size and geographic range," said Marcela Uhart, a medical veterinarian with the Wildlife Conservation Society (WCS). She represents an associate director in Latin America for the WCS Global Health Program. [link to www.livescience.com]